GIVING a director like M Night Shyamalan £84million to make a movie is a bit like giving a ­flamethrower to a five-year-old – you know it’s going to end very badly indeed.

And the man with Hollywood’s most vertiginous career path doesn’t disappoint, with a sci-fi thriller guaranteed to end up in all the Worst Films of the Year lists by December.

Truly, it’s right up there with the heinous John Travolta stinker Battlefield Earth.

A full millennia after humanity abandoned Earth for a new planet called Nova Prime, space ranger Cypher (Will Smith) and his son Kitai (real life son Jaden) crash-land back on Earth.

What follows is 80-odd minutes of the lad running through the devaststed landscape to retrieve a rescue beacon, all the while dodging some badly rendered monsters who sense his fear.

The film has already come under fire for promoting the Scientology credo – Smith Snr is one of the cult’s supporters – but its alleged agenda is the least of After Earth’s problems.

Put bluntly, this is dullness distilled.

While Shyamalan’s dwindling career has been built on the last-minute twist (see The Sixth Sense, The Village, Signs), this time he’s gone for a straight action adventure and it’s not pretty. Kitai’s journey is uninteresting, while Smith Jnr, so good in 2010’s Karate Kid remake, performs with teeth-gnashing awfulness.

Even the speaking clock has more emotional range, with the trite scenes of him bonding with his father simply throw-your-hands-in-the-air bad.

Smith Snr isn’t much better and spends much of the film not acting but spouting risible platitudes about conquering fear that would make even L Ron Hubbard blush.

Calling it the worst film ever may be overstating things but it’s a disaster zone of Chernobyl-esque proportions.